In this article, Forbes.com writes that scientists from Columbia University, IBM and the University of New Orleans announced a new, three-dimensional designer material assembled from two different types of particles only billionths of a meter across.
Self-assembling materials have been around for a while; notable advances have come from several academic researchers and from the labs at Hewlett-Packard. But in previous instances, scientists had figured out how to get layers of material to stack one on top of another, building an intricate structure that is essentially flat. Now IBM, working with academic researchers, made a three-dimensional material that builds itself. The goal is to develop new materials that can be added to existing technology.
Here is a sketch of a self-assembled bimodal superlattice of nanocrystals (Credit: Franz Redl, Kyung Sang Cho, Christopher B. Murray and Stephen O'Brien, IBM T.J. Watson Research Center and Columbia University MRSEC).
To get the material to assemble properly, all of the molecules had to be a specific size -- 11 nanometers for the iron oxide particles, each of which is 60,000 atoms across, and five nanometers across for the lead selenium quantum dots, each of which contains 3,000 atoms. By varying the experimental conditions, the researchers could coax them to assemble into a uniform lattice.
You can find more information by reading "Scientists announce first 3-D assembly of magnetic and semiconducting nanoparticles," a press release from the National Science Foundation which appears today in the journal Nature.
Designing new materials with otherwise unattainable properties, sometimes referred to as "metamaterials," is one of the promises of nanotechnology. Two-dimensional patterns had previously been created from gold nanoparticles of different sizes and mixtures of gold and silver. Extending this concept to three dimensions with more diverse types of materials demonstrates the ability to bring more materials together than previously realized.
"What excites us the most is that this is a modular assembly method that will let us bring almost any materials together," said Christopher Murray, manager of nanoscale materials and devices at IBM Research. "We've demonstrated the ability to bring together complementary materials with an eye to creating materials with interesting custom properties."
And for more images, you can visit this IBM Research page.
Sources: Matthew Herper, Forbes.com, June 25, 2003; National Science Foundation; IBM Research
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